1. Field of the Invention
The present invention relates generally to air diffusers for connecting a duct to an airspace for distributing hot or cold air to the airspace and, more specifically, to such a duct in an air conditioning or heating system with improved insulating properties for preventing moisture condensation in a ceiling installation.
2. Description of the Prior Art
In a typical air conditioning and heating installation, the terminal end of the duct system is fixed to a ceiling or wall and is provided with a diffuser assembly through which air streams are diffused indoors. In the case of a suspended ceiling, the ceiling structure is typically made up of an interlocking grid of struts or tees, suspended from the concrete slab of the roof or the floor of the next storey of the building and having panels of acoustic or similar materials supported on the struts.
To permit communication between the duct work for any air conditioning and heating system and the area located beneath the suspended system, lay-in diffusers are often provided which are capable of resting upon and extending between the array of struts and tees used to support the ceiling panels in position. These diffusers usually have finished bottom portions provided with appropriate louvres or ventilating structures and duct drops are generally provided to connect the duct work with those lay-in diffusers which are being used to ventilate the associated area. Various types of connectors have been provided for connecting the duct with the diffuser, but one problem with such prior connectors was that it was necessary to have a connector of the same size as the air distribution duct, which necessitated providing a separate connector for each size of duct. This meant that several sizes of connectors were required to be stocked, one for each size duct. Often, an installer would not have the right size connector, or connectors, on the job which necessitated a return trip to the shop, or supplier.
Depending upon the desired flow distribution pattern, the air diffuser assembly may assume various forms including planar vane grading, linear slots, pan forms, and the like. The diffuser elements were typically formed of steel, aluminum or other sheet material of a desired shape and were often baked and coated with melamine, or other finish. One commonly seen diffuser is provided with annular diffuser elements of a conical shape in section and spaced at given intervals, the elements being molded of aluminum sheet and coated on their surfaces. Other vane grading type diffusers are well known with the diffuser elements being provided by integral molding of aluminum or other types of sheet material.
The prior art diffuser elements, molded of such metal materials as steel and aluminum sheet, are likely to accumulate indoor moisture on their surfaces and be cooled, resulting in dew condensation. This effect causes the diffusers to become stained or allows dew drops to trickle down into the interior space. As a result, it was usually necessary to apply cut or roll insulation to the outside of the box and associated duct and/or duct connector after it was installed. Cutting and fastening of the insulation to the diffuser is tedious and time consuming and therefore expensive.
A need exists for an improved air duct diffuser for attachment to a ceiling which is provided with a prefromed, insulated backing which does not require a separate wrapping or backing step once the diffuser is installed in place within the ceiling grid.
A need also exists for an improved diffuser which is simple in design and economical to manufacture which has improved thermal properties to lessen or prevent condensation within the diffuser assembly.
A need also exists for a diffuser having an improved means for connection to a variety of different sized air ducts.
A need also exists for such a diffuser having an improved means for suspending a diffuser element or louvre within an associated frame.